Microsoft word - 3510101 pt _35025_ ing.doc

CONTENTS
High-Sensitivity Reagent
PRINCIPLE
3. Plasma Storage
Plasma samples may be stored at 18 to 26oC for up to 2 hours; at 2 The capacity of blood to form a fibrin clot by means of the to 8oC for up to 4 hours; frozen at –20oC for up to 2 months or at – extrinsic hemostatic pathway requires thromboplastin, calcium, 70oC for up to 6 months. Plasma may be re-centrifuged prior to factors I, II, V, VII and X (4,5). The PT-HS reagent provides a freezing to assure that all cells are removed. Quick thaw frozen source of tissue thromboplastin and calcium that specifically samples and test immediately. The samples must not have any activates factor VII in the extrinsic coagulation pathway. The contact with glass. Do not incubate samples at 37oC for longer than factors involved in the intrinsic coagulation pathway are 5 minutes to avoid the loss of factors V and VII. The loosing of Therefore, deficiencies of intrinsic pathway factors (VIII, IX and XII) are not detected using the PT test. INTERFERENCES
REAGENT COMPOSITION
− PT clotting times may be prolonged by substances including PT-HS Lyophilized thromboplastin of rabbit brain and CaCl
corticosteroids, EDTA, oral contraceptives, asparaginase, clofibrate, erythromycin, ethanol, tetracycline and anticoagulants such as heparin and Coumadin. International Sensitivity Index (ISI): 1.07 – 1.39. − PT may be shortened by substances including antihistamines, PT Diluent
butabarbital, caffeine, oral contraceptives, phenobarbital and Optative. Plasma Control Level 1 Ref. 3520101
Plasma Control Level 2 Ref. 3520201.
ADDITIONAL EQUIPMENT
STORAGE AND STABILITY
− Coagulometer or stopwatch and bath at 37ºC ± 0.5ºC. Store at 2-8ºC. The reagents are stable until the expiry date stated on the label. The reconstituted PT-HS reagent is stable for 8 hours at 37ºC and 5 days stored in the original container at 2-8oC. PROCEDURE
This procedure pertains to manual or semi-automated coagulation REAGENT PREPARATION
systems. Refer to your instrument manual for more detailed 1. Reconstitute the contents of PT-HS with one vial of PT Diluent.
2. Replace the stopper and thoroughly mix the vial contents. Let stand for no less than 30 minutes prior to use to assure 1. Pre-incubate the reconstituted PT reagent to 37oC for at least 2. Pipette 50 μL of sample or control plasma into a test cuvette
4. Rapidly add 100 μL of the pre-incubated PT reagent,
Test plasma should be prepared from citrated whole blood without
1. Blood Collection
- Draw venous blood into a plastic or siliconized syringe.
For semi-authomatic system refer to your instrument manual. Immediately transfer 9.0 mL of blood into a tube containing 1.0 mL of 3.2% or 3.8% sodium citrate solution. or, CALCULATIONS
- Draw venous blood into a commercial vacuum tube containing
Calculate the mean clotting time of duplicate samples and controls. Differences between duplicate results should be less than 5%. Insure that a full draw has been obtained since the ratio of 9 parts blood to 1 part citrate is critical. A heparinized lock or transfer lin e should not be used. It is generally recommended that the second or The PT result may be reported as 4 different ways: third tube draw be used for coagulation tests. 2. Plasma Preparation
- Mix well by inversion and centrifuge at 2,500 x g for 15 minutes soon after blood collection. Unless samples are to be processed immediately, transfer the plasma into a plastic tube. Plasma that is clearly hemolyzed or contains > 10,000 platelets per cubic millilitre or red cells is not suitable for coagulation testing. QUALITY SYSTEM CERTIFIED
LINEAR CHEMICALS S.L. Joaquim Costa 18 2ª planta. 08390 Montgat, Barcelona, SPAIN ISO 9001 ISO 13485
Telf. (+34) 934 694 990 Fax. (+34) 934 693 435. website www.linear.es CLINICAL SIGNIFICANCE
The PT reagent is an in vitro diagnostic assay intended for use in performing the one stage prothrombin time (PT) test and assays The INR is recommended for use with patients undergoing anti- which are based on a modified prothrombin time. The prothrombin time is the method of choice for monitoring oral The International Committee for Standardization in Hematology and anticoagulation therapy1 and is a fundamental screening test for the International Committee on Thrombosis and Hemostasis have acquired or inherited bleeding disorders. During oral anti- agreed on recommendations for the reporting of Prothrombin Time coagulation therapy, the activity of vitamin K-dependant clotting results as an International Normalized Ratio (INR). The INR is factors (II, VII, IX, X, Protein C and Protein S) is reduced and PT based on the International Sensitivity Index (ISI) of Thromboplastin time is increased. The test is used for quantitative determination of blood clotting factors in the extrinsic (VII) and common pathways PT reagents are assigned with an ISI value by calibration against an International Reference Preparation (IRP 67/40) with an assigned ISI of 1.0. The ISI value for each lot of PT reagent ANALYTICAL PERFORMANCE
- Linearity: INR 0.8 – 5.0.
The INR is calculated using the following formula: - Sensitivity range: ISI : 1.07 – 1.39.
INR = (Patient PT / Mean Normal PT) ISI

ISI = Specific International Sensitivity Index for the
- Normal PT time mean: 12.0 – 14.7 sec.
Reagent/Instrument system. The ISI is lot specific. - Analytical sensitivity: 3%.
Mean Normal PT = Lot specific mean of the normal range, as
determined by each laboratory for the Reagent /Instrument System. - Traceability: 2 international reference laboratories of WHO , by
It is usually based upon the PT mean plus or minus 2 to 3 standard Standard Rabbit Plain Thromboplastin (WHO Thrombosis Center deviations using 20 or more individuals. REFERENCE VALUES
- Accuracy: Results obtained with this reagent did not show
significative differences when compared with reference reagents. PT results are influenced by the method of clot detection and can Details of the comparison experiments are available on request. vary from laboratory to laboratory. In general, PT tests performed with normal plasmas will give clotting times in the range of 13 to 15 seconds on a photo-optical coagulometer, from 11 to 15 seconds if REFERENCES
a mechanical coagulometer is used, and between 12 and 15 Deykin, D, Anticoagulant therapy. In: Colman, R.W., Hirsh, J, Marder, seconds if the manual method is applied. However, each laboratory V., Salzman, EW (Eds.); Heamostatis and Thrombosis, JB Lippincott, should establish a normal range using individuals representative of its patient population. A new normal range should be established Errichette AM, Holden A, Ansell J; Management of Oral Anticoagulant with any change of instrumentation, blood collection techniques, or Therapy: experience with an Anticoagulation Clinic, Arch. Inter. anticoagulant. A Mean Normal PT range should be reestablished or 3. Hirsh J, Dalen JE, Deykin D., Polter L; Oral Anticoagulants: verified when changing lots of the same reagent (11). Mechanisms of Action, Clinical Effectiveness and Optimal Therapeutic Therapeutic ranges for monitoring oral anticoagulation therapy will vary from laboratory to laboratory. Therefore, it is essential that Miale JB; Laboratory Medicine-Hematology, 4th edition, CV Mosbe, St each laboratory establish relevant PT ranges for its respective 5. Furie B, Furie BC; Molecular and Cellular Biology of Blood Abnormal results obtained with a plasma from a patient not on Coagulation, N Eng J Medicine 326;p800 (1992). Hougie C; The Biochemistry of Blood Coagulation; In Triplett DA, anticoagulant therapy may indicate a factor deficiency or the Laboratory Evaluation of Coagulation, American Society of Clinical presence of an inhibitor. The result may also be due to the effects of certain drugs and medications (12). Additional procedures such as WHO Expert Committee on Biological Standardization, 33 Report. an APTT and mixing studies using factor deficient plasma are Technical Report Series 687, WHO, Geneva (1983). 8. Kirkwood T; Calibration of Reference Thromboplastins and Standardization of the Prothrombin Time Ratio, Thromb Haemostasis QUALITY CONTROL
International Committee for Standardization in Haematology and Control sera are recommended to monitor the performance of International Committee on Thrombosis and Haemostasis. Amer J Clin assay procedures. They should be used as sample. 10. Young DS, Thomas DW, Friedman RB, et al.; Effect of Drugs in REF 3520101 PLASMA CONTROL LEVEL 1
Clinical Tests, Clin Chem 18; p1041 (1972). 11. National Committee for Clinical Laboratory Standards: One-Stage REF 3520201 PLASMA CONTROL LEVEL 2
Prothrombin Time (PT) Test and Activated Partial Thromboplastin Time (APTT) Test, NCCLS Document H47-A (1996). Each laboratory should establish its own Quality Control scheme 12. Laposala M, Connor A, Hicks D, Phillips D: The Clinical Hemostasis and corrective actions if controls do not meet the acceptable handbook, Year Book Medical Publishers Inc. (1989). C35101-2/0802
QUALITY SYSTEM CERTIFIED
LINEAR CHEMICALS S.L. Joaquim Costa 18 2ª planta. 08390 Montgat, Barcelona, SPAIN ISO 9001 ISO 13485
Telf. (+34) 934 694 990 Fax. (+34) 934 693 435. website www.linear.es MASTER CURVE
Introduzca los siguientes valores en el coagulómetro Enter the following values in the coagulometer *Print, and archive the calibration line. This calibration curve is valid for this lot of PT only. C35103-2/0802
QUALITY SYSTEM CERTIFIED
LINEAR CHEMICALS S.L. Joaquim Costa 18 2ª planta. 08390 Montgat, Barcelona, SPAIN ISO 9001 ISO 13485
Telf. (+34) 934 694 990 Fax. (+34) 934 693 435. website www.linear.es

Source: http://www.microbiology.co.ke/pages/PT-HS.pdf